A mold includes a main body and a separable feature. One or more first weakened regions join the separable feature to the main body. The one or more first weakened regions are breakable to enable the main body to be removed from a shell independently of the separable feature after the shell is formed over the mold. The main body includes a first section and a second section that are at least partially separable at one or more second weakened regions to enable the first section to be removed from the shell independently of the second section after the shell is formed over the mold.